Autism is a developmental disorder characterized by impaired social interactions and communication and is normally diagnosed between the years of 2-4. However, the number of people diagnosed with autism has been on the rise in recent years. In a news story released by MSNBC on May 29th 2012 1in 88 children are diagnosed with autism up from 1 in 110 in 2007.2 So what are the possible reasons for the increase in autism?
As part of our investigation into autism this week we discussed possible reasons why autism could be on the rise. One of the possible reasons we mentioned in class is that environmental factors, like consumption of heavy metals and xenobiotics, are causing oxidative stress in the brain and are disrupting biological pathways as a result. In the paper this week researchers suspect the xenobiotics, which are any chemical found in an organism but would not be found in the organism naturally, and heavy metals are causing oxidative stress which is interfering with an enzyme named methionine synthase. The methionine synthase enzyme is responsible for methylating DNA and dopamine-stimulated phospholipids. As a result of fewer methylations, neuron networks are having problems synchronizing with one another and therefore causing problems with attention and cognition. The most likely sources for these heavy metals and xenobiotics are from pharmaceutical medications, food, and possibly from pesticides and herbicides.
Another possible reason why autism has increased in recent years is that doctors have gotten better at diagnosing children with autism. Unfortunately there are no biological or blood test to help identify children with autism. Instead, children are diagnosed by doctors who look for problems with communication, social interaction, and restricted and repetitive behaviors. Additionally, parents are commonly questioned about the child’s behavior to see if it is unusual. As a result of the observations and help from the parents, the doctors are able to determine if the child does or does not have autism.
Finally, vaccines have commonly been associated with the rise in autism in United States. Although there is evidence that vaccines given to children do not lead to autism this idea still persists in the United States. The main ingredient commonly connected with autism is thimerosal which used to be a preservative in vaccines. However, evidence from studies examining trend in autism and vaccine use do not support a connection between thimerosal and autism.3
Although there are several hypothesizes as to what could possibly be causing the increase in autism the true cause is still unknown. Personally, I think, like with most diseases, there is not a single biological problem resulting in autism. Instead I think the rise in autism is due to better diagnostic techniques and an increase in the biological stimuli which are responsible for causing autism. What these stimuli are I am unsure. One thing is for sure, autism will continue to rise until we can determine what is causing the increase in autism cases.